[Bug tree-optimization/69163] New: [6 Regression] ICE in rewrite_use_nonlinear_expr, at tree-ssa-loop-ivopts.c:7086

[doko at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69163

            Bug ID: 69163
           Summary: [6 Regression] ICE in rewrite_use_nonlinear_expr, at
                    tree-ssa-loop-ivopts.c:7086
           Product: gcc
           Version: 6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: doko at gcc dot gnu.org
  Target Milestone: ---

trunk r232077, powerpc64le-linux-gnu, works with -O2

reduced test case:

void fn1(char *p1, char *p2, int p3, int p4) {
  int x, y;
  for (; y; y++) {
    x = 0;
    for (; x < p4; x++) {
      *p1 = *p2;
      p1--;
      p2--;
    }
    p2 += p3;
  }
}

$ g++ -c -g -O3 -Wno-strict-aliasing svga_cirrus.ii
svga_cirrus.ii: In function 'void fn1(char*, char*, int, int)':
svga_cirrus.ii:1:6: internal compiler error: in rewrite_use_nonlinear_expr, at
tree-ssa-loop-ivopts.c:7086
 void fn1(char *p1, char *p2, int p3, int p4) {
      ^~~

0x1094dfbf rewrite_use_nonlinear_expr
        ../../src/gcc/tree-ssa-loop-ivopts.c:7086
0x1094dfbf rewrite_use
        ../../src/gcc/tree-ssa-loop-ivopts.c:7347
0x1094dfbf rewrite_uses
        ../../src/gcc/tree-ssa-loop-ivopts.c:7380
0x109567f3 tree_ssa_iv_optimize_loop
        ../../src/gcc/tree-ssa-loop-ivopts.c:7726
0x109567f3 tree_ssa_iv_optimize()
        ../../src/gcc/tree-ssa-loop-ivopts.c:7758
0x1096f23b execute
        ../../src/gcc/tree-ssa-loop.c:554
Please submit a full bug report,
with preprocessed source if appropriate.